#include <iostream>
#include <vector>


//     hello!

using namespace std;

int main()
{
    vector<vector<int> > vec;
    vector<int> v;

    int i = 0;
    for(i = 0;i < 5;i++)
    {
        v.clear();
        int j = 0;
        for(j = 0; j < 8;j++)
        {
            v.push_back(j*i);
        }
        vec.push_back(v);
    }

    for(i = 0;i < 5;i++)
    {
        int j = 0;
        for(j = 0; j < 8;j++)
        {
            cout << vec[i][j] << " ";
        }
        cout << endl;
    }

    cout << endl <<"行数：vec.size()-> "<<vec.size();
    cout << endl <<"列数：vec[0].size()-> "<<vec[0].size()<<endl;
    cout << "vec[2][3] "<<vec[2][3]<<endl;
}
